Familiarity and Retrieval Monitoring Effects on Dorsal Striatum Connectivity across the Adult Lifespan

Recollection and familiarity-based memory judgments elicit activity in bilateral dorsal striatum. Despite striatal dopamine loss and atrophy with advancing age, the stability of striatal recognition memory effects across the adult lifespan is unknown. We used fMRI to investigate familiarity- and retrieval-monitoring related changes in dorsal striatal connectivity across three age groups. Young, middle-aged, and older adults were scanned as they made associative recognition judgments about previously encoded word pairs. Familiarity and monitoring effects were operationalized as contrasts between studied test pairs incorrectly endorsed as rearranged vs (1) correctly rejected new pairs, or (2) studied test pairs correctly endorsed as intact, respectively. Psychophysiological interaction analyses identified increased familiarity- and monitoring-related functional connectivity with separate bilateral caudate seeds. Familiarity related connectivity changes were observed in left intraparietal sulcus (IPS), right dorsolateral prefrontal cortex (DLPFC), and pre-supplementary motor cortex. Retrieval monitoring connectivity changes were observed in left IPS, left DLPFC, and dorsomedial prefrontal cortex. A region of interest analysis revealed additional monitoring related dorsal striatal coupling with left anterior hippocampus and parahippocampal gyrus. Regression analyses tested the independent contributions of age, recollection performance, and age by recollection interactions on connectivity change. Across all regions, the magnitude of connectivity change was age-invariant after controlling for recollection, with one exception. Compared to young and middle aged adults, the relationship between recollection and monitoring-related striatal-hippocampal coupling among older adults was significantly attenuated. These results suggest a network for tracking familiarity strength during associative recognition memory as well as a potential source of age related memory impairment.